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Health Protocols

Cancer Radiation Therapy

Dietary And Lifestyle Considerations

Importance of Nutrition During Treatment

Radiation therapy can change nutritional needs and alter the body's digestion, absorption, and use of food. Common cancer symptoms and toxic effects of radiation treatment associated with nutritional status include anorexia, weight change, nausea, vomiting, and changes in taste and bowel habits. A study on counseling on the intake of nutrient-dense foods and high-protein liquid formulations showed improved maintenance of body weight and quality of life and reduced anorexia (poor appetite) and diarrhea (Rock 2005).

Specific Nutritional Interventions During Radiotherapy

Low-residue diet. Fiber slows gastrointestinal transit time and thus may not be appropriate for patients at risk for intestinal blockage or patients who have been advised to eat a low-residue (low-fiber) diet (Stubbe 2013). Patients who have had abdominal surgery or abdominal or pelvic irradiation are at increased risk of developing bowel obstruction (NCI 2015; Baxter 2007).

Calorie restriction. Certain dietary strategies, including calorie restriction, the ketogenic diet, or intermittent fasting may enhance chemotherapy or radiation therapy and reduce side effects (O'Flanagan 2017). On a cellular level, the pathways involved in cancer cell metabolism can be targeted with biological agents; those same pathways can also be influenced by calorie restriction. In mice, calorie restriction combined with radiation therapy targeted these pathways and slowed cancer growth, decreased metastases, and prolonged survival (Simone 2016). In humans, the same effect was seen with restriction of carbohydrates rather than full calorie restriction. This type of diet is a ketogenic diet, or a low-carbohydrate, high-fat diet. In a small study of 10 patients with advanced cancer, carbohydrates were restricted to 5% of total calorie intake for 26–28 days. In those patients with higher ketosis (burning fat instead of carbohydrates for energy), partial reversal of several indicators of poor prognosis was observed and insulin was decreased. Patients did lose some weight, although authors indicated the diet is safe (Fine 2012). For patients unable to tolerate a high-fat diet, intermittent fasting may be appropriate, and in those where weight change is not an issue, calorie restriction may be beneficial (Klement 2014).

Multivitamins and antioxidants. In one study of 2264 women, 81% took different antioxidants throughout treatment after a diagnosis of breast cancer. There was a decreased risk of breast cancer recurrence in those taking vitamins C and E and decreased risk of death from any cause in those taking vitamin E. In contrast, there was an increased risk of death from any cause and death from breast cancer in those taking combination carotenoids (Greenlee 2012). That same cohort of breast cancer patients was also assessed for multivitamin use. Those taking a multivitamin before diagnosis and throughout treatment had a reduced risk of breast cancer recurrence and total mortality. Women who took multivitamins before and after diagnosis, ate more fruits and vegetables, and were more physically active had better overall survival (Kwan 2011). The Shanghai breast cancer survivor study, another large trial, did not show the same beneficial effects of vitamins C or E or multivitamin use with radiotherapy, but this may be because fewer patients took a supplement after radiation (Nechuta 2011; Kwan 2011).

Avoid Smoking

Smoking decreases the oxygen-carrying capacity of the blood and leads to poorer treatment outcomes, and it should be avoided in order to improve the efficacy of radiotherapy (Hoff 2012). Smoking also leads to more severe osteoradionecrosis of the jaw in patients with head and neck cancer (Chronopoulos 2015). A 2017 meta-analysis of data from over 40,000 women treated for breast cancer found that the risks of radiation therapy may outweigh the benefits for long-term smokers (Taylor 2017). Women in this situation should consult their healthcare provider about the best treatment course.

Physical Activity

Extensive research shows that exercise is safe during radiotherapy and improves physical functioning, fatigue, and overall quality of life. Patients already on an exercise program prior to receiving radiotherapy may need to decrease the intensity and/or duration of exercise during treatment, but the goal is to maintain exercise as much as possible. For patients who did not exercise prior to radiation, exercises such as stretching and slow walks should be initiated gradually. In some cases, an exercise professional or physical therapist may be helpful (Rock 2012). The section on “fatigue” provides more information on the benefits of physical activity.

For More Information

The complications related to radiation can be acute (such as low blood cell counts) and chronic (gastrointestinal, pulmonary, neuropathic, and cardiac conditions). For more information on some of the topics outlined in this protocol, please consult the following protocols:

Proton Therapy Centers in North America

For a current list of centers visit:

Disclaimer and Safety Information

This information (and any accompanying material) is not intended to replace the attention or advice of a physician or other qualified health care professional. Anyone who wishes to embark on any dietary, drug, exercise, or other lifestyle change intended to prevent or treat a specific disease or condition should first consult with and seek clearance from a physician or other qualified health care professional. Pregnant women in particular should seek the advice of a physician before using any protocol listed on this website. The protocols described on this website are for adults only, unless otherwise specified. Product labels may contain important safety information and the most recent product information provided by the product manufacturers should be carefully reviewed prior to use to verify the dose, administration, and contraindications. National, state, and local laws may vary regarding the use and application of many of the treatments discussed. The reader assumes the risk of any injuries. The authors and publishers, their affiliates and assigns are not liable for any injury and/or damage to persons arising from this protocol and expressly disclaim responsibility for any adverse effects resulting from the use of the information contained herein.

The protocols raise many issues that are subject to change as new data emerge. None of our suggested protocol regimens can guarantee health benefits. The publisher has not performed independent verification of the data contained herein, and expressly disclaim responsibility for any error in literature.